Service manual

OPERATION
3-27
April 2001
Part No. 001-9800-203
group is selected and a dial tone sounds. The number
must then be sent by the user within a few seconds or
normal operation resumes. This mode can be canceled
at any time by pressing any option switch.
3.8.9 TRANSPOND
The transpond feature indicates if the mobile
being called is in service. Transponding is enabled by
programming it in the transceiver being called. Each
selectable group of an LTR system can be
programmed for transpond. Then if a call is received
on one of these groups, the transceiver automatically
transmits two data messages with the second
containing the turn-off code. This causes the trans-
ceiver placing the call to briefly unsquelch and the call
indicator to turn on (if it is programmed on the
selected group). This feature is not available on fixed
priority and block ID codes.
3.9 CONVENTIONAL MODE FEATURES
NOTE: For more information on conventional opera-
tion, refer to Section 3.4.7.
3.9.1 MONITOR MODE
The monitor mode allows all activity on a
channel to be monitored when Call Guard squelch or
other types of squelch control are used (such as
external DTMF or two-tone decoders). The monitor
mode disables these features so that all messages on
the channel are heard. To select the monitor mode,
take the microphone off-hook or press the MON
option switch (see Section 3.6.15). The monitor mode
is indicated by in the display (high tier only).
If microphone off-hook detection has been
disabled by programming, the MON switch must
always be used to select the monitor mode or the
Transmit Disable On Busy feature must be
programmed (see next section). Scanning halts when
the microphone is off-hook (unless off-hook detection
is disabled). However, the monitor switch is not
detected when scanning, so the microphone must
always be used to select monitoring while scanning.
A conventional system must be selected to enable
monitoring. If the MON switch is pressed with an LTR
system selected, NOT CONV is displayed (high tier
only) and monitoring is not selected. If the micro-
phone is taken off-hook with an LTR system selected,
scanning halts (unless off-hook detection is disabled)
but monitoring is not selected.
With high tier models, Call Guard squelch also
can be disabled on the selected system/group by the
CG switch (see Section 3.9.5). This switch disables
both receive and transmit squelch control, while the
monitor mode disables only receive squelch control.
3.9.2 TRANSMIT DISABLE ON BUSY
The Transmit Disable On Busy feature automati-
cally disables the transmitter if the channel is busy
(carrier present) when the PTT switch is pressed. It is
enabled or disabled on each conventional group by
programming. If this feature is not used, the trans-
mitter keys even if the group is busy.
When the transmitter is disabled by this feature,
the busy tone sounds briefly and “DSBL BSY” is indi-
cated on the lower line of the display (high tier only).
The monitor mode (see preceding section) is then
enabled while the PTT switch is pressed so that
activity on the channel can be monitored. It is not
possible to access a channel by holding down the PTT
switch (it must be released to make another attempt).
Some repeaters may have delayed drop-out (hang
time) which causes this feature to disable the trans-
mitter even though no busy condition exists. If this is a
problem, there is the option with this feature to allow
transmitting if the correct receive Call Guard tone or
code is detected. Alternatively, the transmitter can
always be keyed by releasing the PTT switch and then
pressing it again within 1 second.
3.9.3 RECEIVE-ONLY GROUPS
Conventional groups can be PC programmed so
that transmitting is disabled (monitoring only is
allowed). This is done by not programming a transmit
frequency. If the PTT switch is pressed with one of
these groups selected, the intercept tone sounds and
“TX DSBL” is displayed (high tier only).